What rivers feed the Great Salt Lake?

The Great Salt Lake is the largest saltwater lake in the Western Hemisphere and a defining feature of Utah’s landscape. While it has no outlet to the sea, it is sustained by several major freshwater sources that flow into its closed basin. The three principal rivers that feed the Great Salt Lake are the Bear River, the Weber River, and the Jordan River. Together, these rivers deliver more than 95% of the lake’s freshwater inflow, shaping its ecosystem, salinity levels, and seasonal fluctuations.

1. Bear River

The Bear River is the largest of the three rivers that flow into the Great Salt Lake, contributing more than 60% of the lake’s freshwater input. Originating in the Uinta Mountains in northeastern Utah, the river follows a winding 500-mile course through Wyoming and Idaho before looping back into northern Utah and emptying into the northeast arm of the Great Salt Lake.

Length: Approximately 500 miles (805 km), making it the longest river in North America that does not reach the ocean.

Watershed: The Bear River Basin spans over 7,500 square miles.

Importance: In addition to being the lake’s primary freshwater source, the Bear River creates critical wetland habitats for migratory birds in areas such as the Bear River Migratory Bird Refuge.

2. Weber River

The Weber River is the second-largest contributor to the Great Salt Lake. It begins in the Uinta Mountains, flows through Weber Canyon, and passes through the cities of Ogden and Roy before reaching the eastern shore of the lake.

Length: About 125 miles (201 km).

Drainage Basin: Covers approximately 2,400 square miles.

Uses: Much of the river’s flow is diverted for agriculture and municipal use, including irrigation in Weber and Davis counties.

Contribution: Despite these diversions, it remains a significant source of water for the lake’s eastern wetlands and estuarine systems.

3. Jordan River

The Jordan River is a unique tributary that connects Utah Lake to the Great Salt Lake. Flowing northward through the Salt Lake Valley, it winds through the urban core of Salt Lake City before entering the lake near the southern end of its eastern shore.

Length: Approximately 51 miles (82 km).

Source: Flows out of Utah Lake, which itself is fed by several tributaries, including the Provo River, Spanish Fork, and American Fork.

Urban Influence: As it passes through a highly developed area, the Jordan River receives runoff, treated wastewater, and return flows from agriculture and residential zones.

Ecological Role: While its volume is smaller compared to the Bear and Weber Rivers, it plays a vital role in maintaining the southern wetlands and saline shoreline environments.

Other Sources of Inflow

1. In addition to these three main rivers, the Great Salt Lake receives water from:
2. Small creeks and streams from surrounding mountains, especially the Wasatch Range.
3. Direct precipitation, though this is minimal due to the arid climate.
4. Groundwater seepage, which is difficult to quantify but contributes especially near springs and lakebed seeps.

However, evaporation far exceeds precipitation, making the river inflows the lake's lifeblood. In dry years or during prolonged drought, reduced river flow can lead to a dramatic drop in lake levels, increased salinity, and ecological stress.